1. Field of the Invention
The invention relates to an integrated circuit design, and more particularly, to a bandgap reference circuit.
2. Description of Related Art
FIG. 1 is a schematic diagram illustrating a circuit structure for a conventional bandgap reference voltage. A bandgap reference circuit 10 is configured to generate a bandgap reference voltage Vbg. However, the bandgap reference circuit 10 is only operable with collocation of a level detector 20 and a start-up path circuit 30. This is because an amplifier 12 in the bandgap reference circuit 10 requires a specific bias voltage in order to complete a start-up process. Generally, a bias circuit includes the level detector 20 and the start-up path circuit 30. With application requirements, sometimes it requires other circuits for achieving the bias voltage in order to complete the start-up process. The bandgap reference circuit 10 may not complete the start-up process if a path in a specific circuit of the bias circuit does not operate normally. For example, if a switch TG in the start-up path circuit 30 is poorly designed, it usually results in an incomplete start-up process.
In addition, the conventional bandgap reference circuit 10 requires additional bias circuit, thus it may additionally consume more power while increasing overall circuit area. Beside, since circuitry of the bias circuit is complicated, a problem in defective rate may be derived during massive production.